i have had the same problem before its not overwatering you are starting your feedings too early
1st listen to asmalvoice dont feed until some more nodes apear
2nd those 2 lowerleaves are going to turn brown and die dont pull them off until you see the brown apear or the other leaves will start
3rd tap water isnt good for any stage of growth get distilled or leave your water outside for at least 24 haours beause tap contains small amount of bleach